Cushioning textile fabrics are constructed by weaving, knitting, tufting or stitch-bonding, with looping surface yarns engaging each other or looping in and out of a “backing” or “substrate” at intervals having a relatively large spacing. These textile fabrics require stabilization of the surface yarns for use in applications requiring high resistance to abrasion and resistance to planar deformation such as flooring, wallcovering and upholstery. Stabilization of the surface can be achieved by inter-bonding yarns throughout the structure or by locally bonding the lower parts of the loops, located away from the surface. However, inter-bonding of the yarns throughout the structure to a degree sufficient to provide abrasion resistance and dimensional stability under severe end use tends to stiffen the surface of the textile fabric and reduce cushion.
As an alternative, the entire backside of the fabric can be bonded with soft adhesives and optionally attached to various “secondary backings” as in the case of tufted fabrics with the entire backside of the fabric attached adhesively to a backing. While continuous bonding underneath can stabilize the dimensions and the surface of the fabric against abrasion, wear issues and edge fraying remain a problem for fabrics formed with yarn loops spaced apart. In particular, the upper parts of the loops can still degrade with abrasion. Moreover, at the cut edges that are not anchored, relatively long ends of yarns can fray and fuzz during use.
Regarding continuous bonding of the flat or textured backside of looped yarn fabrics, effective bonding also requires highly-fluid low-viscosity adhesives. Examples of these highly-fluid low-viscosity adhesives include latexes and polymeric binders and powdered adhesives carried by liquids. Localized activation also requires controlled adhesive flow into the lower portions of the yarns as well as into and out of the backing or substrate. This controlled adhesive flow is required to be directed into the desired portions of the textile fabric without contaminating the exposed loops of the surface yarns. While avoiding the exposed surface yarns, the process of controlled adhesive flow, exemplified by the common use of latex adhesives applied to the back-laps and the backside of the “primary backings” of a tufted fabric, requires the application of a substantial amount of adhesive to reach all surfaces and to achieve strong bonds. This substantial amount of adhesive stiffens the textile fabric.
As an alternative to controlled adhesive flow, dry adhesives are introduced into or around the backing or substrate. Dry polymeric low melting adhesives tend to have relatively high melt viscosities and require high pressures at elevated temperatures to achieve bonding. These high melt viscosities and the associated high bonding pressures result in “crushing” of the fabric, the loss of thickness and cushion, and increased planar stiffness. While these results are acceptable and even desirable for certain types of “hard-surface”floorcoverings or wallcoverings, they are not suitable for soft-faced floor or wallcoverings and for fabrics requiring conformability, such as upholstery.
A new family of cushioning textile-faced composite structures, aimed mainly at floorcoverings or wallcoverings, utilizes a relatively thick cushioning backing placed under and bonded to a thinner fabric face layer. The fabric face layer may be formed with yarns and can be flat or highly textured. Moreover, the fabric face layer itself may be textured after forming the composite structure, for example, by embossing the desired texture into the fabric face layer. A highly textured surface is usually formed by embossing patterns extending into the composite structure to depths exceeding the original thickness of the fabric face layer. Unless the fabric face layer is severely crushed, collapsed and rigidified across the entire area of the fabric face layer by applying heat and pressure from the top of the composite, yarns in the fabric face layer are not sufficiently stabilized along their entire lengths. For tufted constructions, looping face yarns, which are placed at relatively large intervals along the fabric face layer on a “primary backing”, can easily loosen and can even pull free. For composite structures that are cut into individual tiles such as modular flooring tiles, these looping face yarns can disintegrate along cut edges and “fuzz” as the upper parts of the sectioned loops remain free and burst open upon contact.
Deeply-textured embossed patterns on a textile fabric or composite structure can provide the desired combination of durability, surface stability and dimensional stability and can add plush-aesthetics, cushion, thermal insulation and better planar conformability. However looped textile fabrics and composite structures deeply embossed without prior stabilization with adhesives fail to achieve the desired cut-edge-stability in the face yarns. This lack of edge-stability results from the less-compressed “elevated” areas remaining less-bonded or non-bonded as compared to the more compressed “depressed” areas when the fabric face layers are directly laminated onto a backing as they are embossed. These elevated and less-compressed areas remain vulnerable to wear, abrasion, deterioration, unraveling or “fuzzing”, especially along cut edges.
Tufted yarns are looped by insertion into a primary backing without the loops engaging each other. The tufted yarns also require larger spaces between insertions as compared to knit, stitch-bonded or woven constructions. Unless the entire structure under the pile of tufted yarns, including the “back-laps”, is engaged with and enveloped by adhesive, tufted yarns are subject to tuft pull-out. Therefore, tufted yarns require the use of significant amounts of adhesive, which renders tufted yarn fabrics unsuitable for flexible stand-alone end uses such as upholstery, and for adoption into composites relying on soft backings for cushion. Stand-alone tufted fabrics stabilized with low amounts of adhesives without stiffening the face pile loops, or the entire fabric, and without the total loss of the looped face appearance, are desirable.
Given the limitations of various types of conventional applications of yarns, and particularly involving their use as face layers in modular composite tile flooring, the need exists for the stabilization of fabrics formed with loops of yarns having the desired softness, cushion and wear properties while avoiding wear, abrasion, deterioration, and unraveling or “fuzzing”, especially along cut edges.